1. Field of the Invention
The present invention relates to composite shaped articles based on high-temperature metals or alloys.
2. Description of the Prior Art
High-temperature composites are known in which reinforcing fibers, wires, rods or meshes are embedded in or clad by a heat-resistant metal or alloy. Such composites are disclosed in, for example, "High Temperature Materials in Gas Turbines" by P. R. Sahm and M. O. Speidel, Elsevier, Amsterdam-London-New York 1974; and "Turbine Blades with Thermal Fatigue Resistent Edges" by D. C. Drennen, Batelle Columbus Laboratories, Ohio, Review of Metals Technology, Jan. 28, 1972.
It is known to form such composites by fusion-metallurgical and powder-metallurgical processes, such as by dip-coating, continuous-casting, embedding reinforcing fibers in a powdered matrix in vacuo or by use of plasma spraying. Blanks obtained by such methods are normally compacted, for example, by sintering or extrusion, so as to reduce the cross-sectional area of the composite considerably.
An example of such a known composite is a nickel superalloy reinforced with tungsten fibers or whiskers which, although satisfactory in some respects, suffers from premature embrittlement of the tungsten fibers.
A need, therefore, continues to exist for a method of making composite articles whereby the articles so produced have improved high temperature properties, creep resistance, thermal fatigue properties, and other desirable characteristics; and where the method itself is simple and effective.